ارزيابي علل ايجاد فرسايش آبكندي در بخشي از استان ايلام

Assessment of Affective Factors on Gully Erosion in a Part of Ilam Province, Iran

در اين تحقيق، ارتباط بين ايجاد فرسايش آبكندي و برخي از عوامل خاك شناسي‌، اقليمي‌، نوع كاربري اراضي و شيب در شهرستان درّه‌شهر واقع در استان ايلام مورد بررسي قرار گرفت. براي اين منظور ابتدا مناطق آبكندي تعيين و مجموعاً 18 آبكند خطي، پنجه‌اي و جبهه‌‌اي مورد شناسايي قرار گرفتند. نمونه هايي از خاك مناطق آبكندي از دو افق سطحي و تحتاني ديواره آبكند برداشت گرديد. داده هاي اقليمي از ايستگاه هواشناسي درّه شهر و هم چنين اطلاعات راجع به كاربري اراضي و شيب منطقه نيز از مطالعات صحرايي و نقشه هاي موجود به دست آمد. سپس با استفاده از آزمون تجزيه واريانس ارتباط بين فراواني فرسايش آبكندي در ارتباط با طبقه شيب و كاربري اراضي بررسي و با استفاده از تجزيه و تحليل عاملي و آناليز رگرسيون اقدام به تعيين مهم ترين عامل موثر در ايجاد فرسايش آبكندي گرديد. نتايج تحقيق نشان داد كه بيش تر آبكندها در منطقه با شيب زير 10 درصد ايجاد شده و نوع كاربري اراضي تاثير معني دار در ايجاد آبكندها ندارد. هم چنين درصد رس، درصد شن و ميزان كلسيم مهّم ترين عو

In this study, the relationship between the gully formation and some soil properties, climatic factors, land use and slope was investigated in Dareshahr Township in Ilam Province, Iran. Toward this attempt, 18 axial, digitated and frontal gullies were recognized. The soil samples were taken from the top and subsoil in the gully bank. The climatic, land use and slope information were obtained using Dareshahr Climatic Station and available maps, respectively. The relationship between gully erosion frequency and slope as well as land use was then studied using ANOVA and the most important factor was ultimately recognized by using principle component and regression analyses. The results of the study have shown that most numbers of gullies were formed in areas with slope less than 10% and land uses had no significant effect on gully formation. Besides that, the percentage of clay and sand as well as calcium content were found to be as most affective soil factors on gully formation. Among climatic factors, the rainfall depth and average intensity played important role in gully initiation. The results extracted from discriminate analysis also proved that the depth of rain is the most affective factor in gully formation in the study area.